1. Field of the Invention
The present invention relates to a swelling tape including a polyurethane film, and a method for manufacturing the same. More particularly, the present invention relates to a swelling tape comprising a polyurethane film prepared by coating a polyol and a crosslinker, and a method for manufacturing the same.
2. Description of the Related Art
A swelling tape is used to fill a gap between two subjects and, if necessary, to fix them to each other.
With an increase in demand on mobile phones and mobile equipment, active research and development has been directed toward rechargeable second batteries, but not disposable batteries. For use in mobile equipment, rechargeable batteries need impact resistance. In this regard, a special tape that swells in an electrolyte is recruited so as to protect internal substances from external impacts by making their positions fixed.
Urethane films used in conventional swelling tapes are a T-die extrusion-type that is prepared by T-die extrusion. As of now, T-die extrusion finds a wide range of applications in preparing plastic films.
For T-die extrusion, resin pellets are fed as a film material into a hopper, melted at a high temperature in an extruder, discharged at a predetermined thickness through a T-die, and extruded into a film while passing through holes.
Generally, because the plastic resins are thermoplastic, molten materials are recovered to the original state thereof immediately after T-die extrusion. Thus, the films prepared by T-die extrusion can be readily used immediately after the process. In addition, T-die extrusion is a relatively simple process so that it can be advantageously applied to mass production. However, when characteristic articles, such as colored articles, are produced in a small amount by T-die extrusion, the apparatus should be washed, causing a significant loss of time and raw materials. In addition, when films are prepared by T-die extrusion, their properties are dependent on the materials fed, and thus adjusting and changing these properties are difficult. Further, a material with a high melting point is prone to having a poor appearance, such as gel, fisheyes, etc., when it is not completely melted.
Conventional research into swelling tapes has been directed mainly toward the arrangement of an adhesive layer to achieve a three-dimensional shape through the inflation of a base layer.
Reference may be made to, for example, Korean Patent Unexamined Application Publication Nos. 10-2014-0009089, 10-2014-0063478, 10-2014-0063479, 10-2014-0065592, and 10-2012-0113684. These related arts disclose the formation of a base layer by extrusion and curing or by forming a coated cast layer and curing under light or heat.